JPS58212891A - Welding method of dissimilar diameter pipes - Google Patents

Abstract

PURPOSE:To absorb the errors in dimensional accuracy and in piping without edge preparation and to weld dissimilar diameter pipes without using any welding rod, by melting an insert ring disposed between said pipes in tight contact therewith thereby connecting the dissimilar diameter pipes to each other. CONSTITUTION:An insert ring 5 is prepared in order to weld large and small diameter pipes 1, 2 of piping. The ring 5 is formed to have the outside diameter D larger than the outside diameter d1 of the pipe 1 and to have the inside diameter d3 equal to or larger than the inside diameter of the pipe 2 and smaller than the outside diameter of the piping. The thick walled part of the ring 5 is formed to the ring width W on the outside circumferential side larger than the ring width w on the inside circumferential side thereof, and the side thereof in tight contact with the pipe 1 is made larger than the outside diameter d1 on the inside circumferential side and the side in tight contact with the pipe 2 larger than the outside diameter d2 of the pipe 2 on the inside circumferential side, whereby double layers are formed. Such ring 5 is disposed like a ring 3 between the pipes 1 and 2 in tight contact therewith, and the torch of a welder is positioned at the center of the ring 3 to generate the arc and to melt the ring 3.

Description

[Detailed description of the invention] [Technical field of invention] The present invention relates to a method C for welding pipes of different diameters together.

[Technical background of the invention]

Conventionally, two methods have been adopted for connecting pipes of different diameters: a 7-lunge connection and a connection by welding.The 7-lunge connection method connects pipes of different diameters using 7 langes of different diameters. In addition, as a connection method by welding, a sleeve method and an insertion method are known depending on the size relationship between the diameters of pipes of different diameters.

The sleeve method is a welding method as shown in Figure 1, in which the inner diameter of the sleeve is approximately the same as the outer diameter of the larger pipe (1), the short pipe C, the two-layer pipe (1), and the smaller pipe (1). 2) Insert C2 and weld both ends of the sleeve in the circumferential direction using a welding rod. Plug-in method 1, when the welding method shown in Figure 2 is used, and the inner diameter of the larger pipe (1) is equal to or greater than the outer diameter of the smaller pipe (2).

Delivery! Insert pipe (2) into pipe (1) and weld the end of pipe (1) into which pipe (2) is inserted in the circumferential direction 1 using a welding rod.

[Problems with background technology]

In the above connection method, if the 7:7 Fuji 1 & connection method is used, there is a chance of air leakage due to scratches on the flange surface or deterioration of the 7:7 lunge pongee attachment or ring, which is inferior to the welding connection method. Looking at welded connections using the sleeve method and the plug-in method, firstly, the sleeve method does not require beveling, and by simply increasing the sleeve length, the piping dimensions and installation differences can be made looser than with the arrow alignment method. . However, when welding two layers of C automatically, a #4 mold rod is used, which increases the cost of the welding machine. Welding II! There are many disadvantages that the ji degree becomes small. On the other hand, in the plug-in method, if the inner diameter of the larger diameter pipe is equal to the outer diameter of the smaller diameter pipe, there is no need for beveling, as with the sleeve method, and the dimensional accuracy and installation error of the pipe can be made looser than in the butt method. . However, it is difficult to perform automatic welding! Not only does the RC welding machine that uses a connecting rod increase the cost, but if the inner diameter of the pipe with a larger diameter and the outer diameter of the pipe with a smaller diameter are not equal, it is necessary to process the pipe so that it can be inserted smoothly. to do (
There are two drawbacks. A method of connecting pipes using a reducer is also known, but this method has the disadvantage that the pipes are connected by flanges or welding, and the cost increases by the amount of the reducer.

[Purpose of the invention]

The present invention has been made to eliminate each of the above-mentioned drawbacks.
Its purpose is to provide a method for connecting pipes of different diameters, to absorb dimensional accuracy and installation errors of the pipes without having to bevel the pipes.
It is an object of the present invention to provide a method for welding pipes of different diameters that can be welded without a welding rod.

[Summary of the invention]

In order to achieve the above object, the method for welding pipes of different diameters according to the present invention involves closely arranging two insert rings of pipes of different diameters, melting the insert rings with a welding machine torch, and then welding the pipes of different diameters together. C2 is configured to connect. In addition, as for the configuration of the insert ring, the outer diameter of the ring is larger than the outer pole of the larger pipe of the different diameter pipes to be welded, and the inner diameter of the insert ring is equal to or equal to the inner diameter of the smaller pipe. The ring is formed to be large and smaller than the outside diameter of the pipe, and the thick part of the ring is
The ring on the outer circumference side of the diameter piping is made larger than the ring on the inner circumference side of both pipings of different diameters to form two layers, and the piping is made of aluminum, stainless steel, or iron. It was there.

[Embodiments of the invention]

An embodiment of the method for welding different diameter pipes according to the present invention will be described below with reference to FIGS. 3 and 4.

FIGS. 3(a) and 3(b) are a plan view and an elevation view of an insert ring used in one embodiment of the present invention.

In other words, the outer diameter of the ring is set to be larger than the outer diameter of the pipe with a larger diameter than that of the pipe with a different diameter that comes in contact with the bath, and the inner diameter d8 of the ring is set to be equal to or larger than the inner diameter of the pipe with a smaller diameter, and the inner diameter of the ring is set to be larger than the inner diameter of the pipe with a smaller diameter. The thick part of the ring is formed so that the ring inside W on the outer circumference side is smaller than the inside ring W on the inner circumference side. On the inner circumferential side of the outside &+11 of the large pipe and on the side where the small pipe diameter is close to the g2, the inner circumferential side is larger than the pipe outer diameter aZ of the small pipe diameter to form two layers. 0 #! Figure 4 is a cross-sectional view for explaining the two-layer pipe welding method of the present invention C, in which the pipe with a large diameter (11) and the pipe with a small diameter (2) of the pipes of different diameters to be welded (--the above-mentioned Fig. The insert ring (8) shown in (8) is placed in close contact with the insert ring (8), and the torch of the welding machine is positioned at the center of the insert ring (8) to generate an arc and melt the insert ring +81.

In this way, by using the above-mentioned insert ring, there is no risk of air leakage compared to the conventional 7' (connection of pipes of different diameters, unlike in the case of 7 lange connections of different diameters,
There is no need to expand the piping when welding such as butt, sparse sleeve, and insertion methods, and the desired weld can be obtained by simply attaching an IJ ring and melting the insert ring. I: There is no need to use fittings such as reducers, and the bead width of the welded part after welding can be widened and the tensile strength can be made as strong as the base metal. Furthermore, the occurrence of blowholes during welding is reduced, and the safety of the joint is maintained, providing superior effects not found in conventional pipe connection methods of different diameters.

In addition, the insert ring of the present invention can be manufactured to suit the outside diameter of a large-diameter pipe and the outside diameter and inside diameter of a small-diameter pipe, and can also be manufactured using aluminum or stainless steel. Alternatively, the same applies to different types of piping such as iron (; it has the excellent effect of being able to be manufactured to match the material of the piping, and any type of piping can be used.

〔Effect of the invention〕

As described in detail above, according to the method of welding pipes of different diameters according to the present invention, beveling of the pipe is not required, and dimensional accuracy and installation error of the pipe can be absorbed during automatic #ν, and the welding rod of the present invention can be used. This method has superior effects not found in conventional methods for connecting pipes of different diameters, such as being able to make bath contact with the pipes in just 4 seconds and requiring no special processing.

[Brief explanation of drawings]

Figures 1 and 2 are diagrams for explaining the conventional welding method for pipes of different diameters. Figure (a
) and (b) are a plan view and an elevation view of the insert ring used in the present invention, and FIG. 4 is a cross-sectional view showing the state in which the insert ring in Figure 3 of the helmet is placed in close contact with the piping. (1) I (2) Piping (81 insert ring (4) fillet weld (7317) Agent Patent attorney Kensuke Chika (#1
or 1 person) Figure 1 Figure 4 Torch

Claims (2)

[Claims] (1) Different diameter arrangement i 11J31 Welding of pipes with different diameters characterized by closely arranging two insert rings, and then melting the insert rings with a welding machine torch to connect the different diameter pipes. Method. (2) The outer diameter of the insert ring is larger than the outer diameter of the larger pipe of the different diameter pipes to be welded, and the inner diameter of the ring is the same as or larger than the inner diameter of the smaller pipe and is larger than the outer diameter of the pipe. The ring is small and has a thick wall portion such that the ring on the outer circumferential side of both pipes of different diameters is larger than the ring on the inner circumferential side of both pipes of different diameters to form two layers. A method for welding pipes with different diameters according to claim 1. (81) A method for welding pipes with different diameters according to claim 1, wherein the pipe is made of aluminum, stainless steel, or iron.